I. Field of the Invention
The invention relates generally to an acoustic holographic array, and specifically to an acoustic device for measuring the shape of an object.
II. Related Art
Known systems for forming acoustic discriminator hologram patterns typically include an acoustic transmitter for transmitting acoustic waves at an object to be examined, and an acoustic receiver transducer for detecting acoustic signals from the transmitter which have passed by or through the object or have been defracted or reflected therefrom, the acoustic receiver transducer scanning over a desired area of the object. A sampler takes substantially instantaneous samples of the amplitude of the signals received from the acoustic receiver transducer at predetermined time intervals. Such systems are complicated in construction and require that the acoustic receiver transducer repeatedly scan the object to be measured to produce useful data concerning the shape of the object.
Other systems for measuring the shape of an object include a light source which transmits light toward the object to be measured. A photoelectric sensing unit is positioned behind the object and detects the shadow image of the object and the transition between and light and shadow caused by the boundary of the object. The photoelectric sensing unit detects the amplitude of the light transmitted from the light source through the object and thus can be used to identify characteristics of the shape of the object. However, such systems suffer from the disadvantage that the identified characteristics of the edges of the objects may be distorted due to the shape and composition of the objects. Thus, the accuracy of such systems is reduced.